void annBnds2Box(
const ANNorthRect &bnd_box, // enclosing box
int dim, // dimension of space
int n_bnds, // number of bounds
ANNorthHSArray bnds, // bounds array
ANNorthRect &inner_box) // inner box (returned)
{
annAssignRect(dim, inner_box, bnd_box); // copy bounding box to inner
for (int i = 0; i < n_bnds; i++) {
bnds[i].project(inner_box.lo); // project each endpoint
bnds[i].project(inner_box.hi);
}
}
ANNdecomp tryCentroidShrink( // try a centroid shrink
ES_INFO* es_info,
ANNpointArray pa, // point array
ANNidxArray pidx, // point indices to store in subtree
int n, // number of points
int dim, // dimension of space
const ANNorthRect &bnd_box, // current bounding box
ANNkd_splitter splitter, // splitting procedure
ANNorthRect &inner_box) // inner box if shrinking (returned)
{
int n_sub = n; // number of points in subset
int n_goal = (int) (n*BD_FRACTION); // number of point in goal
int n_splits = 0; // number of splits needed
// initialize inner box to bounding box
annAssignRect(dim, inner_box, bnd_box);
while (n_sub > n_goal) { // keep splitting until goal reached
int cd; // cut dim from splitter (ignored)
ANNcoord cv; // cut value from splitter (ignored)
int n_lo; // number of points on low side
// invoke splitting procedure
(*splitter)(es_info, pa, pidx, inner_box, n_sub, dim, cd, cv, n_lo);
n_splits++; // increment split count
if (n_lo >= n_sub/2) { // most points on low side
inner_box.hi[cd] = cv; // collapse high side
n_sub = n_lo; // recurse on lower points
}
else { // most points on high side
inner_box.lo[cd] = cv; // collapse low side
pidx += n_lo; // recurse on higher points
n_sub -= n_lo;
}
}
if (n_splits > dim*BD_MAX_SPLIT_FAC)// took too many splits
return SHRINK; // shrink to final subset
else
return SPLIT;
}
